This invention relates to exhaust systems for motorcycles. More specifically, this invention relates to an improved exhaust conduit system for maximizing motorcycle engine power output and for minimizing engine noise.
A wide variety of exhaust systems are available in the art for use with motorcycle engines. These systems typically comprise one or more exhaust conduits mounted to extend from the engine to the rear of the motorcycle for directing engine exhaust gases to atmosphere. The exhaust conduits define flow paths for exhaust gases from the engine to atmosphere through associated noise abatement mufflers or the like.
Optimally, these exhaust systems are designed to be relatively lightweight, and to provide a low profile for ease of mounting upon and use with motorcycles. Moreover, it is further desirable to provide a motorcycle exhaust system which places minimum backpressure on the engine in order to maximize engine power output, but at the same time satisfactorily reduce motorcycle engine noise to comply with governmental noise regulations. Unfortunately, the goals of maximum power output together with minimum size and weight are generally incompatible with noise reduction, and compliance with mandatory governmental noise regulations can result in a sacrifice in engine performance.
In exhaust systems in general, some attempts in the prior art have been made to reduce engine backpressure without a corresponding increase in engine noise. These attempts have included, for example, various exhaust gas acceleration and baffle arrangments which typically are relatively bulky, and thereby not conveniently usable on motorcycles. See for example, U.S. Pat. Nos. 2,692,025; 3,043,098; and 3,072,214. Other arrangements more specifically designed for motorcycles have been proposed including crossover duct configurations such as that shown in U.S. Pat. No. 3,949,829, wherein multiple crossover pipes are provided for extending the total length of the exhaust system by crossing exhaust gases from one side of the motorcycle to oppositely-mounted mufflers. However, all of these prior art schemes are relatively complicated in construction.
The present invention overcomes the disadvantages of the prior art by providing an improved exhaust system for motorcycles which is relatively simple in construction, and which effectively reduces engine backpressure and minimizes engine noise.